DC voltage converters are normally used to convert an input-side DC voltage into an output-side DC voltage. In the case of multichannel DC voltage converters, a plurality of different DC voltages may be provided.
DC voltage converters of this type may, for example, be in the form of so-called step-up converters which belong to the group of secondary-clocked switching regulators. In this case, provision is usually made of a storage inductor (as an inductance) as the energy store and a switch, which is operated using a controllable duty ratio. A distinction is made between flyback converters and forward converters depending on the design of the secondary-clocked switching regulators.
Depending on whether or not the coil current returns to zero in the discharging phase of the step-up converter, a distinction is made between two operating modes, namely intermittent and continuous operation. In a DC voltage converter having a plurality of output branches for providing different output voltages, it is necessary, during continuous operation, to ensure that the switches can be fully switched. When designed in integrated fashion, the switches are, for example, field effect transistors.
During intermittent operation, in contrast, the coil current returns to zero in the discharging phase of the coil. In order to nevertheless achieve a useful degree of efficiency, it is necessary to prevent charge carriers from flowing back from the output of the converter to the input. Diodes are normally provided in each branch for this purpose.
The diodes are, for example, designed using integrated circuit technology.